The present invention relates to a surface mount resistor and method for making same.
Surface mount resistors have been available for the electronics market for many years. Their construction has comprised a flat rectangular or cylindrically shaped ceramic substrate with a high conductivity metal plated to the ends of the ceramic to form the electrical termination points. A resistive metal film is deposited on the ceramic substrate between the terminations, making electrical contact with each of the terminations to form an electrically continuous path for current to flow from one termination to the other. The metal resistive film is "adjusted" to the desired resistance value by abrading or by using a laser to remove some of the resistive material. A protective coating is then applied over the resistive film material to provide protection from various environments to which the resistor may be exposed.
One limitation to present prior art designs for surface mounted resistors is that low resistance values less than 1.0 ohms are difficult to achieve. Sophisticated process steps are required and the results are often poor with high per unit manufacturing costs.
Therefore a primary object of the present invention is the provision of an improved surface mount resistor and method for making same.
A further object of the present invention is the provision of an improved surface mount resistor which can produce low resistance values.
A further object of the present invention is the provision of an improved surface mount resistor which utilizes a metal resistance strip in lieu of metal resistance film to achieve very low resistance values and high resistance stability.
A further object of the present invention is the provision of an improved surface mount resistor which is constructed by welding so as to handle the large electrical currents associated with low resistance values.
A further object of the present invention is the provision of an improved surface mount resistor which can use a laser, mechanical abrasion, or both for adjusting the resistive element to the desired resistance value.
A further object of the present invention is the provision of an improved surface mount resistor which incorporates all of the above features and maintains a surface mount design.
A further object of the present invention is the provision of an improved method for making a surface mount resistor which utilizes a "reel-to-reel" manufacturing process which is continuous and which can produce high volumes with low manufacturing cost.
A further object of the present invention is the provision of an improved surface mount resistor and method for making same which are economical in manufacture, durable in use, and efficient in operation.